LONG TRAINING FIELD SEQUENCE CONSTRUCTION

1 . An apparatus for facilitating wireless communication, comprising:

one or more memories; and

one or more processors coupled to the one or more memories, configured to:

select, based on a channel bandwidth of a frame, a high efficiency long training field (HE-LTF) sequence for the frame, wherein the channel bandwidth is divided into a plurality of resource units (RUs), wherein each RU in a set of RUs is allocated to a station (STA) in a set of STAs, wherein the HE-LTF sequence is associated with the allocated RUs;

select an HE-LTF transmission mode from one of a 4× HE-LTF mode, a 2× HE-LTF mode, and a 1× HE-LTF mode;

transmit, to the set of STAs, the HE-LTF sequence; and

transmit, to the set of STAs, a set of additional fields of the frame using the set of allocated RUs and a set of unallocated RUs, wherein the set of additional fields includes a legacy short training field (L-STF), a legacy long training field (L-LTF), a legacy signaling field (L-SIG), a high efficiency signaling A field (HE-SIG-A), and a high efficiency short training field (HE-STF),

wherein the one or more processors transmits the HE-LTF sequence with one or more allocated RUs and none of the unallocated RUs.

2 . The apparatus of claim 1 , wherein each RU comprises a plurality of data and pilot tones.

3 . The apparatus of claim 2 , wherein each RU comprises one of 106 data/pilot tones, 108 data/pilot tones, 26 data/pilot tones, 52 data/pilot tones, 242 data/pilot tones, or 484 data/pilot tones.

4 . The apparatus of claim 3 , wherein the one or more processors are configured to transmit the frame such that the tones within unallocated RUs in the HE-LTF sequence have a value of zero.

5 . The apparatus of claim 1 , wherein the frame is part of a downlink orthogonal frequency division multiple access (OFDMA) transmission and the apparatus is an access point (AP), wherein the AP determines allocation of RUs to the set of STAs.

6 . The apparatus of claim 5 , wherein the AP modulates symbols associated with one or more data/pilot tones allocated to one or more STAs for transmission.

7 . The apparatus of claim 1 , wherein the frame is part of an uplink orthogonal frequency division multiple access (OFDMA) transmission and the apparatus is a non-access point station (non-AP STA), and wherein the set of STAs includes an AP that sets the channel bandwidth of the frame.

8 . The apparatus of claim 1 , wherein the channel bandwidth of the frame is one of 20 MHz, 40 MHz, 80 MHz, 160 MHz, or 80+80 MHz.

9 . A method for facilitating wireless communication, comprising:

selecting, by a wireless device based on a channel bandwidth of a frame, a high efficiency long training field (HE-LTF) sequence for the frame, wherein the channel bandwidth is divided into a plurality of resource units (RUs), wherein each RU in a set of RUs is allocated to a station (STA) in a set of STAs for the frame, wherein the HE-LTF sequence is associated with the allocated RUs;

selecting an HE-LTF transmission mode from one of a 4× HE-LTF mode, a 2× HE-LTF mode, and a 1× HE-LTF mode;

transmitting, by the wireless device to the set of STAs, the HE-LTF sequence; and

transmitting, by the wireless device to the set of STAs, a set of additional fields of the frame using the set of allocated RUs and a set of unallocated RUs, the set of additional fields including a legacy short training field (L-STF), a legacy long training field (L-LTF), a legacy signaling field (L-SIG), a high efficiency signaling A field (HE-SIG-A), and a high efficiency short training field (HE-STF),

wherein the wireless device transmits the HE-LTF sequence with-one or more allocated RUs and none of the unallocated RUs.

10 . The method of claim 9 , wherein the set of unallocated subcarriers includes data subcarriers.

11 . The method of claim 9 , comprising:

transmitting the frame such that tones within unallocated RUs in the HE-LTF sequence have a value of zero.

12 . The method of claim 9 , wherein the frame is part of a downlink orthogonal frequency division multiple access (OFDMA) transmission and the wireless device is an access point (AP) performing:

determining allocation of subcarriers to the set of STAs.

13 . The method of claim 9 , wherein the frame is part of a downlink orthogonal frequency division multiple access (OFDMA) transmission, and wherein the method further comprises:

determining allocation of subcarriers to the set of STAs.

14 . The method of claim 9 , wherein the frame is part of an uplink orthogonal frequency division multiple access (OFDMA) transmission and the wireless device is a non-access point station (non-AP STA), and wherein the set of STAs includes an AP that sets the channel bandwidth of the frame.

15 . The method of claim 9 , wherein the channel bandwidth of the frame is one of 20 MHz, 40 MHz, 80 MHz, 160 MHz, or 80+80 MHz.

16 . A non-transitory machine-readable storage medium that stores instructions, that when executed by one or more processors of a wireless device, cause the wireless device to perform:

selecting, based on a channel bandwidth of a frame, a high efficiency long training field (HE-LTF) sequence for the frame, wherein the channel bandwidth is divided into a plurality of resource units (RUs), wherein each RU in a set of RUs is allocated to a station (STA) in a set of STAs for the frame, wherein the HE-LTF sequence is associated with the allocated RUs;

selecting an HE-LTF transmission mode from one of a 4× HE-LTF mode, a 2× HE-LTF mode, and a 1× HE-LTF mode;

transmitting to the set of STAs, the HE-LTF sequence; and

transmitting to the set of STAs, a set of additional fields of the frame using the set of allocated RUs and a set of unallocated RUs, the set of additional fields including a legacy short training field (L-STF), a legacy long training field (L-LTF), a legacy signaling field (L-SIG), a high efficiency signaling A field (HE-SIG-A), and a high efficiency short training field (HE-STF),

wherein the wireless device transmits the HE-LTF sequence with-one or more allocated RUs and none of the unallocated RUs.

17 . The non-transitory machine-readable storage medium of claim 16 , wherein the set of unallocated subcarriers includes data subcarriers.

18 . The non-transitory machine-readable storage medium of claim 16 , wherein the instructions further cause the wireless device to perform:

transmitting the frame such that tones within unallocated RUs in the HE-LTF sequence have a value of zero.

19 . The non-transitory machine-readable storage medium of claim 16 , wherein the frame is part of a downlink orthogonal frequency division multiple access (OFDMA) transmission and the wireless device is an access point (AP), wherein the instructions further cause the wireless device to perform:

determining allocation of subcarriers to the set of STAs.

20 . The non-transitory machine-readable storage medium of claim 16 , wherein the frame is part of a downlink orthogonal frequency division multiple access (OFDMA) transmission, wherein the instructions further cause the wireless device to perform:

determining allocation of subcarriers to the set of STAs.

21 . The non-transitory machine-readable storage medium of claim 16 , wherein the frame is part of an uplink orthogonal frequency division multiple access (OFDMA) transmission and the wireless device is a non-access point station (non-AP STA), wherein the set of STAs includes an AP that sets the channel bandwidth of the frame.

22 . The non-transitory machine-readable storage medium of claim 16 , wherein the channel bandwidth of the frame is one of 20 MHz, 40 MHz, 80 MHz, 160 MHZ, or 80+80 MHz.